Pleura & peritoneum


Anatomy & histology

Last author update: 1 December 2013
Last staff update: 18 January 2021

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PubMed Search: Pleura[TI] normal histology

Vaidehi Avadhani, M.D.
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Cite this page: Avadhani V. Anatomy & histology. website. Accessed June 1st, 2023.
  • Lungs are surrounded by visceral pleural, a delicate serous membrane arranged as a closed invaginated sac
  • Inner chest cavity is lined by parietal pleural membrane
  • Visceral and parietal pleura define the pleural space / cavity, which normally has minimal volume, unless lungs collapse or air / fluid collects between the two layers
  • Only minimal contact between right and left pleural sacs
  • Regional lymph nodes are internal mammary, intrathoracic, scalene and supraclavicular

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Pleura and chest wall

  • Lined by mesothelial cells overlying vascularized connective tissue
  • Mesothelium provides smooth, low friction surface to facilitate the gliding motion of lungs in pleural cavity, heart in pericardial cavity, viscera in abdominal cavity
  • Gliding facilitated by numerous surface microvilli, thick glycocalyx, secretion of hyaluronic acid and other glycosaminoglycans
Mesothelial cells
Microscopic (histologic) description
  • Monolayer of flat or low cuboidal cells with bland and uniform nuclei, fine delicate chromatin, inconspicuous nucleoli
  • In fine needle aspirates, have well defined cytoplasm and distinct cell borders

Positive stains
Electron microscopy description
  • Apical tight junctions, desmosomes, surface microvilli, cytoplasmic tonofilaments in bundles
Connective tissue cells
Microscopic (histologic) description
  • Resemble fibroblasts

Positive stains
Electron microscopy description
  • Resemble fibroblasts
Black spots
  • Carbonaceous / anthracotic pigments in parietal pleura
  • Present in > 90% of urban dwellers in Belgium at autopsy
  • Not related to hyaline pleural plaques (Am J Surg Pathol 2002;26:1198)
  • Associated with lymphatic drainage
  • Micro description: deposits of opaque particles (intra or extracellular) of various sizes under an intact mesothelial layer, associated with chronic inflammatory cells
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